Natural variability is probably the cause, although global warming could have a role.. Antarctic sea ice shrank to below 2 million square kilometres this year, the lowest minimum extent since satellite records began 43 years ago. The minimum extent of 1.92 million square kilometres occurred on 25 February and was 190,000 square kilometres less than the now second-lowest extent, reached in 2017, the US National Snow and Ice Data Center (NSIDC) reported on 8 March. “The record low for total Antarctic sea ice happened in much the same way as the 2017 event,” says Ryan Fogt, a climatologist at Ohio University in Athens. Both events had an earlier than average maximum sea-ice extent, which was followed by rapid declines, he says. From 2017, the sea-ice extent stayed well below average for a few years, returning to near-average conditions again in 2020.
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